The study will evaluate the safety and effectiveness of Topiramate treatment in amyotrophic lateral sclerosis (ALS). This is a double-blind randomized, placebo-controlled 12 month trial. The objective is to determine whether topiramate slows disease progression in patients with ALS. The primary outcome measure is change in disease progression rate as measured by the maximum voluntary isometric contraction strength of eight arm muscle groups. Secondary endpoints include the rate of decline of forced vital capacity, grip strength, the change in the ALS functional rating scale, and survival.